I'm looking for some Christmas songs I heard some years ago. Can you help identify?

The closest I can think of is "Belleau Wood" by Garth Brooks, but it isn't a close match to what you describe. It recounts the actual event at the battle of the same name, where on Christmas Day, both sides called a truce, sat down at one table, and had a unified Christmas meal. It talks about how the guy was in the trench, and then he heard a German in the German trench singing carols. Then he sang one, and soon everyone was singing. Then he stepped out of his trench and the German came and met him in the middle. It is a very moving song.